Implantable ports are vascular access devices commonly used to deliver or aspirate fluids to or from a target site within a patient for medical treatment. Ports generally have a reservoir that can be accessed by a needle through a self-sealing septum. The reservoir has an outlet stem that is connected to a catheter terminating at a target site within the body, such as the junction of the right atrium and the superior vena cava. The catheter is typically secured to the stem by a locking mechanism, such as a push collar or a twisting lock. The catheter can be connected to the port during various stages of the implantation process, dependent on the preferences of the medical professional performing the procedure, the specifications of the port system, and the nature of the treatment being provided.
Ports can have one or more reservoirs, the most common ports being single or dual reservoir ports. While single reservoir ports typically have a single stem for fluid communication between the reservoir and the catheter, dual reservoir ports typically have two stems arranged in an opposing D-shaped stem profile. The double D stem design features a first and second outlet from a respective first and second reservoir, merging into an opposing D-shaped stem configuration to maintain a circular profile.
Various port locking of varying geometries have been designed to ensure that the catheter remains secured to the outlet stem, and leak-free connection is maintained after implantation. For instance, snap-locks that load over a barbed outlet stem have been used to secure the port catheter. These designs usually feature interlocking elements that mate a collar and catheter to a port body via one or more barbs on the outlet stem. Alternatively, twist looks have been used, which feature a flanged locking member that mates with a void in the port body to secure the lock to the port. In other designs, locking mechanisms have included features such as resilient prongs or live hinges for engaging the locking mechanism to the port body and catheter, securing the catheter to the outlet stem.
There are however a number of drawbacks to types of locking mechanisms described above. Advancing a catheter over a barbed stem can be difficult since the catheter stretches and tightens around the barbs. Since the catheter is flexible, it often kinks as the medical professional tries to advance it over the barbs. Unsuccessful attempts to push the catheter over the barbs can lead to excessive kinking, material deformation, and premature wear and tear on the catheter, compromising its integrity and durability. Pushability of the catheter over the stem is further encumbered by the fact that the medical professional connecting the catheter to the stem is wearing sterile gloves. In addition, gloves are often wet and slippery from contact with fluids associated with performing port insertion procedures. Further, locks with engaging components such as flanges or live hinges require twisting the lock to a particular radial orientation prior to loading, so that the engaging components are in-line to mate. The complexity of these systems also adds to the profile of the locking mechanism at the catheter/port junction, increasing the footprint of the port in the port pocket. Complex locking systems also increase manufacturing and end user costs. Additionally, locking mechanisms with resilient members be less durable and more difficult to manufacture. There remains a need for an improved locking system that allows for easy catheter loading over a barb-free stem, ensures a secure and leak-free connection, is operable to engage under any radial orientation and is simple to manufacture at a low cost.